- The Faceless: Originally, an actor was chosen to play Sebastian and publicity stills were taken of him in costume before Williams decided that Sebastian's face should never be seen, stating that his presence was made all the more powerful by his absence.
- Method Acting: After the climatic scene in which Catherine recalls Sebastian's death, Elizabeth Taylor fell into hysterics and couldn't stop crying. She had been drawing on her grief from the recent death of her husband to act out the scene.
- Spiteful Spit: During the actual production. Several years prior, actor Montgomery Clift (Dr. Cukrowicz) had suffered a near-fatal car accident that left him in near-constant pain for the rest of his life. Suddenly, Last Summer was one of the first films he made after his return to acting, having spent several years recovering from both the accident and a subsequent alcohol and painkiller addiction. Due to his physical mobility issues, there were points during the production where he could only film a few lines at a time before needing to take a break. The cast and crew were sympathetic to Clift, but director Joseph Mankiewicz was openly disgusted and impatient with him and called several times to replace him. This treatment infuriated hot-tempered Katharine Hepburn. After Mankiewicz called the final "cut!", Hepburn asked if he was absolutely sure filming was complete and that he wouldn't need her for anything else. When he told her he wouldn't, she spat in his face and stormed out of the studio.
Trivia / Suddenly, Last Summer